Homework problems. 1. A function, (concat X Y), that will concatenate two lists, X and Y. 2. A function, (del X L), that will delete a scalar, X, from a list, L. 3. A function, (mean L), that returns the average value of a list, L. 4. A function, (compare X Y), that compares two lists, X and Y, and returns a true if the are equal, or else a nil. 5. A function, (reverse X Y), which reverses the list X onto the list Y and returns the result. If Y is nil, then the result should be the reverse of X. 6. A function, (palindrom X), which return a t or nil if the list X is a palindrom or not. 7. A function, (uniq X), that returns a list that is composed of the members of X, such that no element of X appears in the result more than once. 8. A function, (uconc X Y), which produces a uniq concatenation of X and Y. 9. A function, (diff X Y), which produces the members of X that are not in Y and the members of Y that are not in X. 10. A function, (gcd X Y), which returns the greatest common denominator of X and Y using Euclids algorithm.